AQA GCSE Physics: Combined Science

Topic Questions

5.3 Forces & Elasticity

1a3 marks

Which of the following statements is correct about inelastic deformation?

Tick (✓) three boxes.

   

 Object returns to its original length square
Object returns to its original shape  square
Object does not return to its original length square
Object does not return to its original shape  square
Requires only one force  square
Requires more than one force square
1b1 mark

What are the correct units for the force applied to a spring which makes it elastically deform?

Tick (✓) one box.

   

square
N m  square
N/m  square
N square
1c1 mark

Which of the following options is the correct equation linking Force (F), spring constant (k) and extension (e)?

Tick (✓) one box.

   

F space equals space k e squared square
F space equals 1 half k e square
F space equals space k e square
F space equals space 2 k e square

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2a1 mark

Figure 1 shows a force-extension graph for a spring.

Figure 1

5-3-e-2a-force-extension-graph

Which marker on the force-extension graph shows the limit of proportionality?

Tick (✓) one box.

 

square B  square C  square D square

2b1 mark

Which marker on Figure 1 shows the spring obeying Hooke's law?

Tick (✓) one box.

 

square B  square C  square D square

2c1 mark

State the quantity given by the gradient of a force-extension graph.

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3a1 mark

Write the equation linking elastic potential energy open parentheses E subscript e close parentheses, spring constant open parentheses k close parentheses and extension open parentheses e close parentheses.

3b1 mark

A spring has a spring constant k. The force exerted on the spring is increased so that the extension doubles.

How does this affect the work done on the spring?

Tick (✓) one box.

   

Work done doubles  square
Work done halves square
Work done increases by a factor of 4 square
Work done decreases by a factor of 4 square

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1a2 marks

A group of physics students are investigating force and extension of a spring.

One student obtained the results shown in Table 1.

Table 1

Mass / kg Force / N Mean total length / m Extension / m
0 0 0.051 0
0.2 1.96 0.074 0.023
0.4 3.92 0.091 0.017
0.6 5.88 0.108 0.017
0.8 7.84 0.127 0.019
 

As the teacher came around to check the student's data, the teacher asked the student to think about why the extension data is not increasing.

Identify the mistake the student has made in their data analysis process.

1b2 marks

Another student plotted their graph, but the shape of the curve was different to everybody else's. 

Figure 1 shows the student's graph.

Figure 1

5-3-h-1b-ef-graph

 

Suggest what the student did to produce the graph shown in Figure 1.

1c1 mark

Another student extrapolated their graph as shown in Figure 2.

Figure 2

5-3-h-1c-force-extension-extrapolation

What is the significance of the point marked X?

Tick (✓) one box.

   

X shows the original length of the spring  square
X shows the average extension of the spring square
X shows the final length of the spring after deformation square
X shows the increased length of the spring after deformation square

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2a1 mark

Figure 1 shows a force-extension graph for a spring with a spring constant k.

Figure 1

5-3-h-2a-force-extension-k

Draw a line on Figure 1 for a spring with a higher value of k.

2b5 marks

A force of 2 N causes a spring to extend by 3 cm.

Calculate the extension of the spring when a 3.5 N force is applied.

Give your answer in cm to 2 significant figures.

   

   

Extension (2 significant figures) = .................................... cm

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3a2 marks

A student plotted a force-extension graph for a spring of spring constant k

Figure 1 shows the graph they plotted.

Figure 1

5-3-h-3a-force-extension-anomaly

The student has labelled one of the data points as anomalous. 

State whether you agree with this choice, and explain your answer.

3b4 marks

For the spring used in part (a), calculate the work done on the spring when a 3 N force is applied.

Give your answer in the appropriate units.

   

   

Work done = .................................... Units = ....................................

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13 marks

A newton meter, as shown in Figure 1, consists of a point, connected to a metal spring.

When a force is applied to the spring, the spring stretches, and the point moves along the scale.

Figure 1

newton-meter

Use the information provided in the diagram to calculate the spring constant of the spring.

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26 marks

A student wishes to carry out an investigation to measure the spring constant of a metal spring.

Describe a method that the student could use.

Your answer should include detail of how accurate measurements may be taken and may also include a labelled diagram

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3a6 marks

The table below gives the results obtained by the student.

Force in N Extension in cm
2.0 1.3
4.0 2.1
6.0 2.9
8.0 3.7
10.0 4.5
12.0 5.9

The student finds that after stretching, the spring does not return to its original length.

Plot a graph of force (y-axis) against extension (x-axis) on the grid below.

q3a-5-3-aqa-gcse-physics

3b2 marks

Mark the position of the elastic limit on the graph, using an X.

Give your reason for choosing this point.

3c2 marks

The student has made an error whilst calculating some of the results.

Suggest what the error was and how the results could be corrected.

3d3 marks

Use the graph to calculate the spring constant of the metal spring.

3e2 marks

The student decided to repeat the experiment using a double spring set up, as shown in Figure 2

Figure 2

double-spring

Add a line to your original graph showing the results you would expect the student to get.

You should assume that the initial extension of the springs is the same as with the original experiment.

3f2 marks

Explain how the elastic limit of the double spring will compare with the original spring.

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4a2 marks

Figure 3 shows three different stages in a bungee jump.

Figure 3

bungee

Stage 1: The jumper is stationary and the bungee cord is slack

Stage 2: The bungee cord has no slack, but is not yet exerting a force on the jumper.

Stage 3: The jumper is at the lowest point and has temporarily stopped moving.

Describe the change in energy stores that occur between stage 1 and stage 3.

4b3 marks

Calculate the change in the jumper’s gravitational energy store between stage 1 and stage 2.

The jumper has a mass of 60 kg (assume that the mass of the bungee cord is negligible).

Gravitational field strength = 10 N/kg

4c1 mark

State the energy in the jumper’s kinetic store at stage 2.

4d3 marks

Calculate the speed of the bungee jumper at stage 2.

4e1 mark

After reaching stage 2, the bungee cord starts to stretch, exerting an upwards force on the jumper which eventually brings the jumper to a stop at stage 3.

Between stage 1 and stage 3 the jumper’s gravitational energy store decreases by a total of 18 000 joules.

State the energy in the bungee’s elastic store at stage 3.

4f1 mark

Calculate the extension of the bungee cord at stage 3.

4g3 marks

Using an appropriate equation from the Physics equation sheet, calculate the spring constant of the bungee cord.

You may assume that the bungee cord behaves like a perfect spring.

4h3 marks

Use your answers to (f) and (g) to calculate the force exerted by the bungee cord on the jumper at stage 3.

4i2 marks

At stage 3 the jumper's spine stretches a small but safe amount.

Explain why

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